Linux/BIOSLINUXMCSDK: OMAP L138 Can't Change Linux Console UART

David L62

Part Number: BIOSLINUXMCSDK
Other Parts Discussed in Thread: OMAPL138, DA8XX

Tool/software: Linux

I am working with a custom OMAP L-138 based board that is similar to the LCDK. Our board uses UART0 for the console, the LCDK uses UART2. I am trying to modify the existing LCDK code to use UART0. The changes I have made so far allow U-Boot to use UART0, but after Linux is copied into memory and I get the message "Starting Linux ...", I don't get any more console output from Linux. Using the JTAG debugger, I can see that Linux is loading into memory and running, just no console output.

I'm using MCSDK 1.01.00.
I modified omapl138_lcdk.h and omapl138_lcdk.c to get U-Boot working on UART0
I modified the CONFIG_BOOTARGS definition changing console=ttyS2 to console=ttyS0 assuming Linux would use UART0 for the console after the change, but it didn't work.

Please advise me on the proper method of changing the UART in Linux. Thanks.

over 6 years ago

0 Kemal R. Shakir over 6 years ago

TI__Guru 55345 points

Hello David,

Commented out these two lines at <MCSDK install dir>/board-support/linux-<version>/arch/arm/mach-davinci/board-omapl138-lcdk.c file.

__raw_writel(0, IO_ADDRESS(DA8XX_UART1_BASE) + 0x30);
__raw_writel(0, IO_ADDRESS(DA8XX_UART0_BASE) + 0x30);

Best regards,
Kemal

0 David L62 over 6 years ago in reply to Kemal R. Shakir

Prodigy 40 points

Thanks Kemal. I see where the edits you recommended are necessary. I implemented the changes and rebuilt uImage, but still don't get any output from UART0. Other than the changes to the Linux kernel you recommended, I have not made any other changes. Can you think of anything else I might be missing?

Thanks again,
David

0 Kemal R. Shakir over 6 years ago in reply to David L62

TI__Guru 55345 points

Please, check this thread.

Processors

Processors forum

Linux/BIOSLINUXMCSDK: OMAP L138 Can't Change Linux Console UART